Technical Field
The present disclosure relates to semiconductors, and more particularly, to semiconductor structures having insulator pillars and a semiconductor material on a substrate, and a method of forming the same.
Related Art
As complementary metal-oxide semiconductor (CMOS) technologies continue to scale down in size, creating smaller semiconductor structures has become more challenging. As a result, alternate semiconductor materials, such as silicon germanium or III-V semiconductors, are being considered as options for advanced technology nodes. One particular challenge related to advanced technology nodes is forming these alternative semiconductor materials directly on a substrate. In particular, due to the lattice mismatch between these semiconductor materials and the substrate, the semiconductor materials may become highly strained as they are grown on the substrate. To overcome this high strain, the semiconductor materials are grown to be very thick, i.e., about 1 micrometer (μm) to 2 μm, to allow relaxation of the alternate semiconductor materials near the substrate. Additionally, the lattice mismatch causes defects to form at an interface of the substrate and the semiconductor material grown thereon. Therefore, the semiconductor material must also be grown to a thickness such that the defects terminate, and at least a portion of the semiconductor material over the defects is defect free.
Aspect ratio trapping (ART) refers to a process by which defects are trapped within trenches within non-crystalline material. ART has been employed to reduce the thickness of the semiconductor material grown on a substrate. ART includes forming a non-crystalline material on substrate and etching trenches within the non-crystalline material. Subsequently, semiconductor material may be formed within the trenches over the substrate. As previously discussed, defects may form between the semiconductor material and substrate. However, since the semiconductor material is formed within the trenches within the non-crystalline material, the defects will terminate at a surface of the non-crystalline material. That is, the defects will be smaller in size due earlier termination within the trenches created during the ART process.